1. Field of the Invention
The present invention relates to a substrate dryer for drying a semiconductor substrate, a glass substrate for a liquid crystal display unit, a glass substrate for a photomask, a substrate for an optical disk or the like (hereinafter simply referred to as xe2x80x9csubstratexe2x80x9d) cleaned with de-ionized water (pure water).
2. Description of the Background Art
In general, a surface treatment such as etching with a chemical solution or cleaning with de-ionized water and a drying treatment are successively performed on the aforementioned substrate, to achieve a series of substrate treatments. In such series of treatments, the drying treatment is generally executed as the final treatment following finishing cleaning with de-ionized water.
In general, the substrate is dried by a method (the so-called spin drying) of rotating the substrate at a high speed and draining water by centrifugal force or a method employing IPA (isopropyl alcohol). Following recent complication of the semiconductor device structure, however, a drying failure called as a water mark is noted, and the drying method employing IPA hardly causing this problem is now forming the mainstream. The water mark, which is a drying spot caused by moisture adhering to the surface of the substrate and reacting with silicon forming the substrate and oxygen contained in the air to form particles, is readily caused as the time when the moisture adheres to the surface of the substrate increases.
The drying method employing IPA includes a method (IPA vapor drying) of spraying vapor of IPA onto the surface of the substrate to which moisture adheres or a method (Marangoni drying) of pulling up and passing the substrate through a thin liquid layer of IPA formed on the surface of de-ionized water. IPA substitutes for the moisture adhering to the surface of the substrate and vaporizes in a short time, to relatively hardly cause a water mark in the drying method employing IPA.
As generally known, however, importance is recently attached to environmental problems, while IPA applies load on the environment if discharged as such. In any of the aforementioned methods, therefore, a prescribed disposal treatment must be performed for making IPA harmless to the environment. However, such a disposal treatment requires a considerably high cost as a matter of course, to disadvantageously increase the cost for the substrate treatment.
Further, the structure of a device formed on the surface of the substrate is recently so refinedxc2x7complicated that the problem of a water mark may arise also in the drying method employing IPA. In Marangoni drying, further, a Marangoni convection formed on the interface between the liquid layer of IPA and the de-ionized water may disadvantageously result in transfer of particles adhering to the surface of the substrate.
The present invention is directed to a substrate dryer for drying a substrate cleaned with de-ionized water.
According to a first aspect of the present invention, a substrate dryer for drying a substrate cleaned with de-ionized water comprises a cleaning bath storing de-ionized water for dipping a substrate in the de-ionized water thereby cleaning the substrate, a pull-up robot pulling up the cleaned substrate from the cleaning bath, and a drying gas supply part supplying drying gas containing silicone gas to the main surface of the substrate being pulled up by the pull-up robot.
Silicone can suppress formation of a water mark also on a substrate having a refinedxc2x7complicated structure due to its excellent permeabilityxc2x7dryability while applying no load to the environment. Therefore, no specific treatment is required for disposing silicone but increase of the cost required for the drying treatment can be suppressed.
According to another aspect of the present invention, a substrate dryer for drying a substrate cleaned with de-ionized water comprises a cleaning bath storing de-ionized water for dipping a substrate in the de-ionized water thereby cleaning the substrate, a pull-up robot pulling up the cleaned substrate from the cleaning bath, and a drying gas supply part supplying drying gas containing gas of a fluorine-based inactive liquid to the main surface of the substrate being pulled up by the pull-up robot.
The fluorine-based inactive liquid can suppress formation of a water mark also on a substrate having a refinedxc2x7complicated structure due to its excellent permeabilityxc2x7dryability while applying no load to the environment. Therefore, no specific treatment is required for disposing the fluorine-based inactive liquid but increase of the cost required for the drying treatment can be suppressed.
According to still another aspect of the present invention, a substrate dryer for drying a substrate cleaned with de-ionized water comprises a cleaning bath storing de-ionized water for dipping a substrate in the de-ionized water thereby cleaning the substrate, a pull-up robot pulling up the cleaned substrate from the cleaning bath, and a silicone layer forming part supplying a drying liquid containing silicone to the surface of the de-ionized water stored in the cleaning bath for forming a silicone layer, while the pull-up robot pulls up the cleaned substrate from the cleaning bath thereby passing the substrate through the silicone layer formed on the surface of the de-ionized water stored in the cleaning bath.
Silicone allows no adhesion of particles onto a substrate having a refinedxc2x7complicated structure due to its excellent permeabilityxc2x7dryability while applying no load to the environment. Therefore, no specific treatment is required for disposing silicone but increase of the cost required for the drying treatment can be suppressed.
Accordingly, an object of the present invention is to provide a substrate dryer causing no water mark also on a substrate having a refinedxc2x7complicated structure and capable of suppressing increase of a cost required for a drying treatment.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.